Histopathologic examination revealed prominent parakeratosis of the stratum corneum. The epidermis displayed irregular epidermal hyperplasia with a few scattered individual dyskeratotic keratinocytes and a cluster of pale epidermal keratinocytes. The papillary dermis was mildly edematous, and there was a perivascular lymphohistiocytic infiltrate.

Zinc sulfate therapy (5 mg/kg per day) was begun, and initial signs of improvement occurred within 2 days. His initial zinc level was 0.2 µmol/L (1.2 µg/dL) (reference range, 10.4-19.9 µmol/L [68-130 µg/dL]). His skin was clear 2 weeks after he began the therapy, and he showed normal smiling and laughing behavior for the first time. He continued to do well, with blood zinc levels in the normal range. Nine and a half months after zinc therapy was initiated, the maintenance dose was cut in half. The patient continued to do well, and 2 months later, the zinc therapy was discontinued. However, the eruption recurred 2 weeks later on the patient's cheeks, and zinc therapy was restarted. The patient has remained asymptomatic with therapy as he approaches his third birthday.